The problems came to light last month when the VA announced five patients were sickened at its Oakland hospital on University Drive, then later revealed one had died.

Since then, the VA has confirmed the hospital has had 29 Legionnaires' cases since January 2011, including the five announced in November. Eight more cases were traced to bacteria in the hospitals water, but the VA says it can't be sure if the other 16 people got sick at the hospital or caught the disease elsewhere.

The U.S. Centers for Disease Control is also investigating and Doyle, a Pittsburgh-area Democrat, wants a House committee hearing.